1. Field of the Invention
The present invention relates to a device and a method for cutting semiconductor-crystal bars.
2. Description of the Related Art
Conventionally, single-crystal silicon ingots, polycrystalline silicone ingots, or compound semiconductor ingots (hereinafter referred to as semiconductor-crystal bars) are cut into wafers or blocks by employing the following methods: namely, a method using an internal-blade grind wheel, the thin doughnut shaped internal rim of which is bonded with grind particles such as diamonds; a method using an endless band saw that is a thin-link shaped strip steel with grind particles such as diamonds bonded thereon; or a wire-saw cutting method in which a thin piano wire is shifted constantly so as to cut a semiconductor-crystal bar by segregated grind particles.
However, for the cutting processes in which internal blades or endless band saws are utilized, thin plates bonded with grind particles such as diamonds are used. Accordingly, it is difficult to slice a semiconductor-crystal bar into wafers of thinness less than 0.2 mm. In addition, the outer rims of the wafers break off easily. In the method that utilizes wire saws, it is necessary regularly to exchange the piano wires which become thin. Furthermore, oil-rich grind particles are used; therefore treating waste fluid or cleaning the oil sticking on the wafers is a time-consuming and costly process.